Mode division multiplexing(MDM)is becoming a hot topic in the field of optical fiber communication. It can increase the capacity of optical fiber communication exponentially by using the limited and orthogonal spatial modes of few-mode fiber to transmit information in parallel. In this paper, we present a thorough review of recent progress in MDM in terms of system modeling, equalization, and development of system experiment. Firstly, we give a detailed description of the equalization method used for demultiplexing and analyze its computational complexity. Then, we summarize some recent experimental demonstrations of MDM, including the particular structure of the system and main results. Finally, we give some possible research directions for MDM.

fiber communication  /  mode division multiplexing  /  few-mode fiber  /  multiplexer/demultiplexer